I propose to investigate the role of specific DNA-protein complexes in the regulation of gene expression. Various transcription complexes with SV40 tumour virus DNA and E. Coli lactose promoter DNA will be studied by "in vitro" transcription and DNA methylation. Sequenced hybrid DNA fragments containing combinations of known promoter mutations in the lac operon will be constructed. The role of SV40 DNA structure in regulation will be probed using various forms of SV40 DNA, including mini-chromosomes. Correlation of altered methylation patterns of DNA in transcription complexes with altered RNA synthesis will identify the function of precise base pair sequences as regulatory elements. Both E. Coli and mammalian RNA polymerases will be used to study eukaryotic transcription. It is hoped that study of these genes will lead to understand normal and abnormal cellular regulation in humans.